Because of size reduction of a chip inductor, a coil and a mounting board on which the coil is mounted are close to each other. When the coil and the mounting board are close to each other, the interaction between the coil and a conductor pattern on the mounting board increases.
Japanese Unexamined Patent Application Publication No. 2005-45103 discloses a chip inductor in which a Q-value is increased by decreasing the degree of linkage of a magnetic flux generated by a coil to a conductor pattern on a mounting board. The chip inductor includes a multilayer body composed of a plurality of laminated insulating layers on which coil conductor patterns are formed. The plurality of coil conductor patterns are continuous between the insulating layers and form one coil. Terminal electrodes are provided at both end portions of the multilayer body in a direction perpendicular to the lamination direction of the multilayer body, and extended portions at both ends of the coil are connected to the terminal electrodes. The chip inductor is mounted on the mounting board in an attitude in which the lamination direction (coil axis direction) is perpendicular to the mounting board.
When the surface of the multilayer body that faces the mounting board is referred to as lower surface, the coil is disposed at a position shifted to the upper side of the multilayer body. Since the distance between the coil and the mounting board is increased, the degree of linkage of the magnetic flux generated by the coil to the conductor pattern on the mounting board decreases. As a result, it is possible to increase the Q-value of the inductor.
Japanese Unexamined Patent Application Publication No. 2002-260925 also discloses a chip inductor in which a coil is disposed so as to be shifted to the upper side. According to this configuration, the stray capacitance between the coil and a circuit board or an outer electrode of the chip inductor is reduced, and thus the resonant frequency is increased. As a result, the frequency characteristics of the inductance are improved.
Japanese Unexamined Patent Application Publication No. 9-148143 discloses a mounting structure in which a mounting board is provided with a cavity that faces a mounted position of a choke coil and that has dimensions having a width at least equal to or larger than the width of the choke coil and a length equal to or larger than the length of a coil portion of the choke coil. By providing a ground pattern around the cavity, air having a dielectric constant lower than the dielectric constant of the mounting board is present in the gap between the mounting board and the choke coil, so that it is possible to reduce a stray capacitance component.
When the number of windings of the coil is increased in a configuration in which the coil is located so as to be shifted to the upper side of the multilayer body and in an attitude in which the coil axial direction and the mount surface of the mounting board are perpendicular to each other, the dimension of an element in a height direction is increased. On the other hand, in the case of avoiding an increase in the dimension in the height direction, since it is not possible to increase the number of windings of the coil, it is difficult to obtain a high inductance.
In the configuration in which the cavity is provided in the mounting board, it is not possible to dispose a wire at a position corresponding to the cavity, and thus a wiring-enabled region of the mounting board becomes narrow. Furthermore, a manufacturing step of forming the cavity in the mounting board is required, and thus there is a disadvantage in terms of manufacturing cost.